Method for subscription and notification in m2m communication system and apparatus for same

ABSTRACT

The present invention relates to a method performed in a machine-to-machine (M2M) device comprising a first resource and a second resource, and an apparatus for the same. The method comprises the steps of: adding first condition information to filtering properties of the first resource; receiving, from a first entity, a request message including first information indicating an address corresponding to the second resource and second information indicating an operation to be performed in the device; and transmitting a notification message to a second entity indicated by address information set in the first resource when predetermined conditions are satisfied, wherein the predetermined conditions include (1) a condition that the second resource should correspond to a parent resource of the first resource and (2) a condition that the first condition information should include a parameter corresponding to the operation, and wherein the first resource and the second resource respectively show data structures which are uniquely addressable by using unique addresses.

TECHNICAL FIELD

The present invention pertains to a Machine-to-Machine (M2M)communication system. More specifically, the present invention pertainsto a method and apparatus for subscribing and notifying an operationperformed for a specific resource in a M2M system.

BACKGROUND ART

Recently, interest in M2M (machine-to-machine) communication is rising.The M2M communication corresponds to communication performed betweenmachines without a human involvement. The M2M communication is alsoreferred to as MTC (machine type communication) or IoT (internet ofthings) communication. A terminal used for the M2M communication isreferred to as a M2M device. In general, the M2M device hascharacteristics such as low mobility, time tolerant or delay tolerant,small data transmission and the like. The M2M device is used in a mannerof being connected with a M2M server, which stores and manages M2Mcommunication information at the center. If a M2M device is connectedaccording to a communication scheme different from each other, the M2Mdevice and the M2M server are connected with each other via a M2Mgateway in a section where a communication scheme is changed. In doingso, a whole M2M system may be constructed. Such a service as objecttracking, power metering, automatic payment system, healthcare service,remote controlling, and the like may be provided by the M2M system.

The present invention relates to a M2M system.

DISCLOSURE OF THE INVENTION Technical Object

An object of the present invention is to provide a method forefficiently transmitting and receiving a signal in a M2M system and anapparatus therefor.

Another object of the present invention is to provide a method forefficiently performing subscription/notification for a specific resourcein a M2M system and an apparatus therefor.

Still another object of the present invention is to provide a method forefficiently subscribing and notifying an operation performed for aspecific resource in a M2M system and an apparatus therefor.

Still another object of the present invention is to provide a method ofsubscription and notification based on an operation performedirrespective of a status change of a subscription target resource in aM2M system and an apparatus therefor.

It is to be understood that technical objects to be achieved by thepresent invention are not limited to the aforementioned technicalobjects and other technical objects which are not mentioned herein willbe apparent from the following description to one of ordinary skill inthe art to which the present invention pertains.

Technical Solution

In an aspect of the present invention, provided herein is a methodperformed by a Machine-to-Machine (M2M) device in which a first resourceand a second resource are configured, the method comprising: addingfirst condition information or second condition information to afiltering attribute of the first resource; receiving a request messagefrom a first entity, the request message comprising first informationindicating an address corresponding to the second resource and secondinformation indicating an operation to be performed by the device; andwhen a specific condition is satisfied, sending a notification messageto a second entity indicated by address information configured in thefirst resource, wherein the specific condition includes (1) the secondresource corresponds to a parent resource of the first resource, (2)when the filtering attribute of the first resource comprises the firstcondition information, the first condition information comprises avariable corresponding to the operation, (3) when the filteringattribute of the first resource comprises the second conditioninformation, and when the second resource or a child resource of thesecond resource is changed by the operation, the second conditioninformation comprises a variable corresponding to a changed status ofthe second resource or the child resource of the second resource, andwherein each of the first resource and the second resource represents adata structure which is uniquely addressable using a unique address.

In another aspect of the present invention, provided herein is aMachine-to-Machine (M2M) device in which a first resource and a secondresource are configured, the M2M device comprising: a network interfaceunit; and a processor, the processor configured to add first conditioninformation or second condition information to a filtering attribute ofthe first resource, receive a request message from a first entity, therequest message comprising first information indicating an addresscorresponding to the second resource and second information indicatingan operation to be performed by the device, when a specific condition issatisfied, send a notification message to a second entity indicated byaddress information configured in the first resource, wherein thespecific condition includes (1) the second resource corresponds to aparent resource of the first resource, (2) when the filtering attributeof the first resource comprises the first condition information, thefirst condition information comprises a variable corresponding to theoperation, (3) when the filtering attribute of the first resourcecomprises the second condition information, and when the second resourceor a child resource of the second resource is changed by the operation,the second condition information comprises a variable corresponding to achanged status of the second resource or the child resource of thesecond resource, and wherein each of the first resource and the secondresource represents a data structure which is uniquely addressable usinga unique address.

Preferably, the first condition information is used for monitoringwhether an operation of accessing the second resource or the childresource of the second resource is attempted irrespective of whether theoperation of accessing the second resource or the child resource of thesecond resource is performed.

Preferably, the variable indicates at least one of creation, retrieval,update, or deletion.

Preferably, the notification message comprises a parameter correspondingto the operation.

Preferably, when the second condition information is added to thefiltering attribute of the first resource, the notification messagecomprises a parameter corresponding to the changed status.

Preferably, the specific condition further includes (4) the secondentity sending the request message has a retrieve permission for thesecond resource, (5) when the first entity and the second entity aredifferent from each other, the first entity has an access right forsending a notification message to the second entity.

Preferably, the first resource corresponds to a resource forsubscription, and the second resource corresponds to a subscriptiontarget resource.

Advantageous Effects

According to the present invention, it is able to efficiently transmitand receive a signal in a M2M system.

According to the present invention, it is able to efficiently performsubscription/notification for a specific resource in a M2M system.

According to the present invention, it is able to efficiently subscribeand notify an operation performed for a specific resource in a M2Msystem.

According to the present invention, it is able to subscribe and notifybased on an operation performed irrespective of a status change of asubscription target resource in a M2M system.

It will be appreciated by persons skilled in the art that the effectsthat can be achieved with the present invention are not limited to whathas been particularly described hereinabove and other advantages of thepresent invention will be more clearly understood from the followingdetailed description taken in conjunction with the accompanyingdrawings.

DESCRIPTION OF DRAWINGS

The accompanying drawings, which are included to provide a furtherunderstanding of the invention, illustrate embodiments of the inventionand together with the description serve to explain the principle of theinvention.

FIG. 1 illustrates an example of a M2M system.

FIG. 2 illustrates an example of a layered structure of a M2M system.

FIG. 3 illustrates an example of a functional architecture of a M2Msystem.

FIG. 4 illustrates an example of a M2M system configuration.

FIG. 5 illustrates an example of a resource used in a M2M system.

FIG. 6 illustrates an example of a resource for a M2M application.

FIG. 7 illustrates an exemplary communication flow of a general M2Msystem.

FIG. 8 illustrates an example of different entities interoperating witheach other in a M2M system.

FIG. 9 illustrates an example of a procedure related to a subscriptionresource.

FIG. 10 illustrates an example of a notification procedure.

FIG. 11 illustrates an example of using a subscription resource.

FIG. 12 illustrates an exemplary method for an operation subscriptionaccording to the present invention.

FIG. 13 illustrates an embodiment according to the present invention.

FIG. 14 illustrates a block diagram of a device to which the presentinvention is applicable.

DETAILED DESCRIPTION

The preferred embodiments of the present invention will now be describedin detail with reference to the accompanying drawings. The detaileddescription, which will be given below with reference to theaccompanying drawings, is intended to explain exemplary embodiments ofthe present invention, rather than to show the only embodiments that canbe implemented according to the present invention. The followingdetailed description includes specific details in order to provide athorough understanding of the present invention. However, it will beapparent to those skilled in the art that the present invention may beimplemented without such specific details.

When describing the present invention, in order to avoid obscuring theconcepts of the present invention, a well-known structure or device maybe omitted and important functions of the structures and devices may beshown in a form of block diagram. The same reference numbers will beused throughout the drawings to refer to the same or like parts.

In the present invention, a machine-to-machine (M2M) device refers to adevice for M2M communication. The M2M device may be fixed or mobile. TheM2M device may transmit and receive user data and/or control informationto/from a M2M server by communicating with the M2M server. The M2Mdevice may be referred to as terminal equipment, Mobile Station (MS),Mobile Terminal (MT), User Terminal (UT), Subscriber Station (SS),wireless device, Personal Digital Assistant (PDA), wireless modem,handheld device, etc. In the present invention, the M2M server may referto a server for M2M communication, and may be implemented as a fixedstation or a mobile station. In the present invention, when a network towhich a M2M device is attached and a network to which a M2M server isattached are different from each other, a M2M gateway refers to anapparatus serving as a connection point entering from one network to theother network. Further, a M2M gateway may perform a function as a M2Mdevice, and, for example, may perform a function such as managing a M2Mdevice connected to the M2M gateway, receive one message and forward themessage or a modified message to M2M devices connected to the M2Mgateway, or a message aggregation. The term “M2M device” may be used tocollectively refer to a M2M gateway and a M2M server, and thus a M2Mgateway or a M2M server may be referred to as a M2M device.

In addition, in the present specification, the term “entity” may referto a hardware such as a M2M device, a M2M gateway, or a M2M server, orthe term “entity” may refer to a software component of M2M applicationlayer or M2M (common) service layer as described below.

In the present specification, the present invention is described on thebasis of a M2M system, but the present invention is not limited to theM2M system. For example, the present invention may be applied to asystem in accordance with a client-server (or sender-responder) model ina similar/same manner.

FIG. 1 illustrates an example of a M2M system. FIG. 1 illustrates anexample of a M2M system in accordance with ETSI (Europeantelecommunications standards institute) TS (technical specification).

The M2M system in accordance with the ETSI TS defines a common M2Mservice framework for various M2M applications. A M2M application mayindicate a software component implementing such a M2M service solutionas e-health, city automation, a connected consumer, automotive and thelike. The M2M system provides functions commonly required forimplementing the various M2M applications, and the commonly requiredfunctions may be referred to as a M2M service or a M2M common service.If the M2M common service is used, a M2M application may be easilyimplemented without configuring a basic service framework again for eachM2M application.

The M2M service is provided in a form of a set of service capability(SC), the M2M application may access the set of SC (service capability)via an open interface and may use a M2M service or function provided bythe SC (service capability). SC may provide a function constructing aM2M service (e.g. device management, location, discovery, groupmanagement, registration, security, etc). A service capabilities layer(or SC layer) or a service capability entity (or SC entity) maycorrespond to a set of functions for a M2M service which may be usedwhen a M2M application is provided on a service framework.

The SC (service capability) may be represented as xSC. In this case, xmay be represented by one of N, G and D. The x indicates where the SC(service capability) exists among a network (and/or a server), a gatewayand a device. For example, NSC indicates SC (service capability)existing in a network and/or a server, and GSC indicates SC (servicecapability) existing in a gateway.

A M2M application may exist in a network, a gateway or a device. The M2Mapplication existing in a network or a directly connected with a servermay be referred to as a M2M network application, or may be simplyreferred to as a NA (network application). For example, the NAcorresponds to software which is implemented in a manner of beingdirectly connected with a server, and the NA may perform a role ofcommunicating with a M2M gateway or a M2M device and managing the M2Mgateway and the M2M device. The M2M application existing in the devicemay be referred to as a M2M device application, or may be simplyreferred to as a DA (device application). For example, the DAcorresponds to software which is implemented in a M2M device, and the DAmay be able to deliver sensor information and the like to the NA. TheM2M application existing in the gateway may be referred to as a M2Mgateway application, or may be simply referred to as a GA (gatewayapplication). For example, the GA may play a role of managing a M2Mgateway, and the GA may provide a M2M service or function (e.g. SCs(service capabilities) or SC (service capability)) to the DA. The M2Mapplication may collectively refer to an application entity (AE) or anapplication layer.

Referring to FIG. 1, a M2M system architecture may be divided into anetwork domain and a device and gateway domain. The network domain mayinclude functions for M2M system management and functions for networkmanagement. The functions for the M2M system management may be performedby M2M SCs (service capabilities) and a M2M application managing deviceexisting in the device and gateway domain. The function for networkmanagement may be performed by a core network and an access network.Hence, in the example shown in FIG. 1, the core network and the accessnetwork provide connection between entities rather than performing a M2Mfunction. M2M communication may be performed between M2M SCs (servicecapabilities) in the network domain and the device and gateway domainvia the core network and the access network. A M2M application of eachdomain may give and take a signal or information via M2M SCs (servicecapabilities) of a corresponding domain.

The access network corresponds to an entity enabling a M2M device andgateway domain to communicate with a core network. Examples of theaccess network include xDSL (digital subscriber line), HFC (hybrid fibercoax), satellite, GERAN, UTRAN, eUTRAN, wireless LAN, WiMAX and thelike.

The core network corresponds to an entity providing a function such asIP (internet protocol) connection, service and network control,interconnection, roaming and the like. The core network includes a 3GPP(3^(rd) generation partnership project) core network, an ETSI TISPAN(telecommunications and internet converged services and protocols foradvanced networking) core network, a 3GPP2 core network, and the like.

M2M SC (service capability) provides a M2M common service function (CSF)capable of being shared by various M2M network applications, andexposures a M2M service via an open interface, thereby enabling M2Mapplications to use the M2M service. A layer including such M2M SCentities or M2M common service functions may be referred to as M2M SCL(service capability layer).

A M2M application corresponds to an entity operating service logic andbeing capable of using M2M SCs (service capabilities) via an openinterface. A M2M application layer may refer to a layer including theM2M application and a related operational logic.

A M2M device corresponds to an entity operating a M2M device applicationvia M2M SCs (service capabilities). The M2M device may directlycommunicate with a M2M server of a network domain, or may communicatewith the M2M server of the network domain via a M2M gateway. In case ofbeing connected via a M2M gateway, the M2M gateway operates like aproxy. The M2M device may include a M2M application and/or M2M SCs(service capabilities).

A M2M area network provides connectivity between a M2M device and a M2Mgateway. In this case, a network between the M2M gateway and a M2Mserver and a network between the M2M device and the M2M gateway may bedifferent from each other. For example, the M2M area network may beimplemented using a PAN (personal area network) technology such as IEEE802.15.1, Zigbee, Bluetooth, IETF ROLL, ISA 100.11a and a local networktechnology such as PLC (power line communication), M-BUS, wirelessM-BUS, KNX and the like.

The M2M gateway is an entity managing a M2M application via M2M SCs(service capabilities) and providing a service to the M2M application.The M2M gateway may perform a role of a proxy between a M2M device and anetwork domain and may perform a role of providing a service to an ETSInon-compliant M2M device. The M2M gateway may refer to an entity havinga function of a gateway among M2M devices. The M2M gateway may include aM2M application and/or M2M SCs (service capabilities).

The M2M architecture shown in FIG. 1 is just an example and a name ofeach entity may vary. For example, M2M SC (service capability) may bereferred to as a M2M common service function (CSF), and a SCL (servicecapability layer) may be referred to as a common service layer (CSL) orcommon service entity (CSE). A M2M application may be referred to as anapplication entity (AE), and a M2M application layer may be simplyreferred to as an application layer. Similarly, a name of each domainmay vary as well. For example, in one M2M system, a network domain maybe referred to as an infrastructure domain, and a device and gatewaydomain may be referred to as a field domain.

As shown in FIG. 1, a M2M system may be construed as a layered structureincluding a M2M application layer and a M2M SC (service capability)layer for M2M communication.

FIG. 2 illustrates an example of a layered structure of a M2M system.

Referring to FIG. 2, a M2M system may include an application layer 202,a common service layer 204 and an underlying network services layer 206.As described in the above, application layer 202 may correspond to a M2Mapplication layer, and common service layer 204 may correspond to a M2MSCL. Underlying network services layer 206 provides services such asdevice management, a location service and device triggering to commonservice layer 204 in a core network.

FIG. 3 illustrates an example of a functional architecture of a M2Msystem. In terms of functionality, M2M system architecture may includean application entity (AE) 302, a common service entity (CSE) 304, andan underlying network service entity (NSE) 306. Each of entities 302,304, 306 may communicate with each other via a reference point supportedby common service entity 304. The reference point plays a role indesignating a communication flow between entities 302, 304, 306. Thereference point may be represented as Mcx, and Mc means “M2Mcommunications”. In the present specification, a Mca reference point, aMcc reference point and a Mcn reference point may be denoted as Mca, Mccand Mcn, respectively.

Referring to FIG. 3, Mca reference point 312 designates a communicationflow between application entity (AE) 302 and common service entity (CSE)304. Mca reference point 312 enables AE 302 to use a service provided byCSE 304, and enables CSE 304 to communicate with AE 302. Mca referencepoint 312 may indicate an interface between a M2M application layer anda M2M common service layer (or entity).

Mcc reference point 314 designates a communication flow betweendifferent common service entities (CSEs) 304. Mcc reference point 314enables CSE 304 to use a service of another CSE when CSE 304 provides arequired function. A service provided by Mcc reference point 314 may bedependent on the functions supported by CSE 304. Mcc reference point 314may indicate an interface between M2M common service layers.

Mcn reference point 316 designates a communication flow between CSE 304and underlying network service entity (NSE) 306. In order to make CSE304 provide a required function, Mcn reference point 316 enables the CSEto use a service provided by NSE 306. Mcn reference point 312 mayindicate an interface between the M2M common service layer and the M2Munderlying network layer.

In the example shown in FIG. 3, CSE 304 may provide various commonservice functions (CSFs). For example, CSE 304 may include at least oneof an application and service layer management function, a communicationmanagement and delivery handling function, a data management andrepository function, a device management function, a group managementfunction, a discovery function, a location function, a network serviceexposure/service execution and triggering function, a registrationfunction, a security function, a service charging and accountingfunction, a service session management function, or asubscription/notification function. CSE 304 represents an instance ofthe common service functions and provides a subset of the common servicefunctions capable of being used and shared by M2M applications. Thecommon service functions are briefly explained in the following.

-   -   Application and service layer management (ASM): provides a        function of managing AEs and CSEs. For example, the ASM function        may configure a function of a CSE, troubleshoot the function of        the CSE, and upgrade the function Moreover, the ASN function may        upgrade a function of an AE.    -   Communication management and delivery handling (CMDH): provides        a communication with another CSEs, AEs and NSEs. For example,        the CMDH function may determine when and how to use a connection        for CSE-to-CSE communication and may control specific requests        to be delivered in a manner of being delayed.    -   Data management and repository (DMR): enables M2M applications        to exchange and share data with each other. For example, the DMR        function may collect a great amount of data, aggregate the data        with each other, convert the data into a specific format, and        store the converted data.    -   Device management (DMG): manages a device function not only for        a M2M gateway and a M2M device but also for devices existing in        a M2M area network. For example, the DMG function may perform        application installation and configuration, firmware update,        logging, monitoring, diagnostics, network topology management        and the like.    -   Discovery (DIS): searches for information such as information        and a resource within a given range and condition according to a        request.    -   Group management (GMG): For example, a group may be generated by        combining a resource, a M2M device or a M2M gateway with each        other, this function handles a group-related request.    -   Location (LOC): This function enables a M2M application to        obtain location information of a M2M device or a M2M gateway.    -   Network service exposure/service execution and triggering        (NSSE): enables communication of an underlying network to be        performed and makes a service or a function provided by the        underlying network available.    -   Registration (REG): This function enables a M2M application or        another CSE to register to a specific CSE. Registration is        performed to use a M2M service function of the specific CSE.    -   Security (SEC): performs a role in handling of sensitive data        such as a security key, establishing security-related        association, authentication, authorization, protecting ID        (identity) and the like.    -   Service charging and accounting (SCA): performs a role in        providing a charging function to an AE or CSE.    -   Service session management (SSM): performs a role in managing a        M2M session of a service layer for end-to-end communication.    -   Subscription/notification (SUB): in case of subscribing a change        of a specific resource, when the resource is changed, performs a        role of notifying the change.

FIG. 4 illustrates an example of a M2M system configuration. In thepresent specification, a node corresponds to an entity including one ormore M2M applications or an entity including one CSE and zero or moreM2M application.

A node including at least one or more application entities (AEs) but notincluding a common service entity (CSE) may be referred to as anapplication dedicated node (ADN). The ADN may communicate with onemiddle node (MN) or one infrastructure node (IN) via a Mca. The ADN maybe referred to as a M2M device having a constrained capability. In thiscase, the M2M device having a constrained capability may correspond to aM2M device not including a common service layer or a common serviceentity (CSE). The M2M device having a constrained capability may besimply referred to as a constrained M2M device.

A node having at least one common service entity (CSE) and at least oneor more M2M application entity (AE) may be referred to as an applicationservice node (ASN). The ASN may communicate with one middle node or oneinfrastructure node via a Mcc. The ASN may be referred to as a M2Mdevice.

A node including one common service entity (CSE) and zero or more M2Mapplication entity (AE) may be referred to as a middle node (MN). The MNmay communicate with one infrastructure node (IN) or another middle node(MN) via a Mcc. Or, the MN may communicate with IN/MN/ASN via the Mcc.Or, the MN may communicate with an ADN via a Mca. The MN may be referredto as a M2M gateway.

A node having a common service entity (CSE) and including zero or moreapplication entity (AE) may be referred to as an infrastructure node(IN). The IN may communicate with at least one middle node (MN) and/orat least one ASN. Or, the IN may communicate with one or more ADNs via aMca. The IN may be referred to as a M2M server.

Referring to FIG. 4, case 1 shows an example of communication performedbetween ADN 402 and IN 422. ADN 402 may correspond to a M2M devicehaving a constrained capability. In this case, since ADN 402 does notinclude a CSE or a common service layer, ADN 402 may communicate with aCSE of IN 422 via Mca. In this case, since ADN 402 does not include aCSE or a common service layer, ADN 402 may not store data generated byan AE or an application layer of AND 402 and may not share the data withanother entity. Hence, in the case 1, the data generated by the AE orthe application layer of ADN 402 may be stored and shared in the CSE ofIN 422.

Case 2 shows an example of communication performed between ADN 404 andMN 414. ADN 404 may also correspond to a M2M device having a constrainedcapability. Hence, ADN 404 may operate similarly to an operation of case1 except that ADN 404 is communicating with a CSE of MN 414. Inparticular, the ADN 404 may communicate with the CSE of the MN 414 via aMca. And, since ADN 404 does not include a CSE or a common servicelayer, ADN 404 may not store data generated by an AE or an applicationlayer of AND 404 or share the data with another entity. Hence, the datagenerated by the AE or the application layer of ADN 404 may be storedand shared in the CSE of IN 414.

Meanwhile, in case 2, MN 414 may communicate with IN 422 via MN 412. Inthis case, MN 414 and MN 412 may communicate with each other and MN 412and IN 422 may communicate with each other via Mcc. MN 414 maycommunicate with IN 422 without passing through MN 412.

Case 3 shows an example of communication performed between ASN 406 andMN 414. Unlike case 1 or case 2, since ASN 406 includes a CSE or acommon service layer, data generated by an AE or an application layer ofASN 406 may be stored in the CSE or the common service layer of ASN 406.And, the AE of ASN 406 may communicate with a CSE of MN 414 via the CSEof ASN 406.

Case 4 shows an example of communication performed between ASN 408 andMN 414. Compared to case 3, a CSE of ASN 408 may directly communicatewith a CSE of IN 422 without passing through a MN.

IN 422 or 424 may be located in an infrastructure domain or a networkdomain and may include one CSE and zero or more AE. INs 422, 424 maycommunicate with each other via Mcc.

FIG. 5 illustrates an example of a resource used in a M2M system.

In a M2M system, an application entity (AE), a CSE, data and the likemay be represented as a resource. In a M2M system, a data structure thatcan be uniquely addressed using a unique address (e.g., URI (universalresource identifier or uniform resource identifier)) is referred to as aresource. In a M2M system, a resource may be represented as a specificdata structure, and resources may be logically connected with eachother. Hence, a M2M device, a M2M gateway, a CSE or a common servicelayer of a M2M server may include a resource. On the contrary, an AE orapplication layer of the M2M system may not have a resource. A resourcehas a child resource and an attribute. A root resource of a M2M resourcemay have an attribute and a child resource. For example, a type of theroot resource may be denoted by <baseURI> or <CSEBase>. A resource typemay be denoted by “<” and “>”.

Various resources are defined in a M2M system. M2M applications mayperform communication based on a resource which is an instantiation of aresource type. For example, a resource may be used for a M2M servicesuch as registration of an application, reading a sensor value and thelike. When an instance of a corresponding resource type is generated,unique address information (e.g., URI) is given to each resource.Similar to a root resource, each resource may include an attribute and achild resource, and may be addressed using unique address information. Aspecific resource type defines a child resource and an attribute which aresource may have when instantiation. When an instantiation of aspecific resource is performed, a resource may have an attribute and achild resource defined by a resource type of the specific resource.

An attribute stores information about a resource itself and may notinclude a child resource. A child resource may include an attribute anda child resource of its own. For example, a child resource may be aremote CSE resource, an application entity resource, an access controlresource, a container resource, a group resource, a subscriptionresource, and the like.

-   -   Remote CSE resource: includes information of another CSE        registered (connected) to a corresponding CSE. For example, a        type of the remote CSE resource may be denoted by <entity> or        <remoteCSE>.    -   Application entity resource: a resource located under an        application entity resource (e.g. <baseURI>/<application> or        <CSEBase>/<AE>) of a root resource or a remote CSE resource        (e.g. <baseURI>/<entity> or <CSEBase>/<remoteCSE> of a root        resource. If an application entity resource is located under an        application entity resource (e.g. <baseURI>/<application> or        <CSEBase>/<AE>) of a root resource, the application entity        resource stores information of an application entity registered        (or connected) to a corresponding CSE. If an application entity        resource is located under a remote CSE resource (e.g.        <baseURI>/<entity> or <CSEBase>/<remoteCSE> of a root resource,        the application entity resource stores information of an        application entity registered to a specific remote CSE. For        example, a type of an application entity resource may be denoted        by <application> or <AE>.    -   Access control resource: a resource storing information related        to access rights. Authorization may be performed using access        right information included in the access control resource.    -   Container resource: stores data per CSE or AE. For example, a        container resource may be denoted by <container>.    -   Group resource: enables a function of grouping several resources        into a group and processing as one group. For example, a type of        a group resource may be denoted by <group>.    -   Subscription resource: performs a function of notifying a change        of a resource status via a notification. For example, a type of        a subscription resource may be denoted by <subscription>.

FIG. 6 illustrates an example of a resource for a M2M application. Asdescribed in the above, a resource for a specific M2M application may bestored in an application resource among resources of a CSE or commonservice layer of a M2M gateway. The resource for the specific M2Mapplication may have an attribute and a child resource. In the exampleof FIG. 6, a child resource is represented as a type (e.g. denoted by“<”, “>”) and a real name of the child resource is assigned and storedwhen an instantiation is performed.

FIG. 7 illustrates an exemplary communication flow of a general M2Msystem. In general, an operation of a M2M system may be performed on thebasis of data exchange. For example, in order for a specific device tostop an operation of another device, the specific device may transmit acorresponding command to the another device in a form of data. In orderto store data in a device, a data structure having a specific format maybe used, and this data structure is referred to as a resource. Theresource may be accessible using a unique address (e.g., URI).

Referring to FIG. 7, a Request and Response Scheme may be used forAE-to-CSE connection or CSE-to-CSE connection. An originator maytransmit a request message to a receiver so as to request a resourcestored in the receiver, and may receive a response message in responseto the request message. Likewise, the receiver may receive a requestmessage for requesting a resource from the originator, and may transmita response message to the originator upon receiving the request message.In the present specification, the request message may also be referredto as a request, and the response may also be referred to as a response.A request message to be transmitted from the originator to the receivermay have the following information.

-   -   op: a form of operation to be executed. ‘op’ may be one of        Create, Retrieve, Update, Delete, or Notify. In the present        specification, information corresponding to operation may be        referred to as a command.    -   to: URI of a target resource.    -   fr: identification information (or ID) of an originator having        generated the request.    -   mi: meta information regarding the corresponding request.    -   cn: content of a resource to be transferred.

If the corresponding request is successfully carried out, the responsemessage may include the following information. The response message mayinclude at least one of the following information, or may include onlythe result value (rs).

-   -   to: identification information (or ID) of an originator having        generated the request.    -   fr: identification information (or ID) of a receiver having        received the request.    -   mi: meta information regarding the request.    -   rs: the result (e.g., Okay, Okay and Done, Okay and in progress)        of the request.    -   ai: additional information.    -   cn: content of a resource to be transmitted.

If the corresponding request fails, the response message may include thefollowing information.

-   -   to: an originator having generated the request.    -   fr: ID of a receiver having received the request.    -   mi: meta information regarding the request.    -   rs: the result (e.g., Not Okay) of the request.    -   ai: additional information

In the present specification, an originator indicates a transmitterdevice (or a CSE or an AE of the transmitter device) and a receiverindicates a receiver device (or a CSE or an AE of the receiver device).And, a device including a resource (or a CSE of the device) is referredto as a hosting device (or a hosting CSE).

As an example, an originator may use a scheme shown in an example ofFIG. 7 to create a resource in a receiver. In this case, the originatormay send a resource creation request message (e.g., CREATE request) tothe receiver. The resource creation request message may includeinformation described in the following.

-   -   op: C (Create)    -   to: URI of a parent of a creation target resource    -   fr: originator ID    -   cn: includes attribute information of the creation target        resource, and optionally includes identification information        (e.g., a name) of the creation target resource.

When the receiver receives the resource creation request message, thereceiver checks whether the originator has been authenticated. Sinceinformation (e.g., access rights or an access control policy) about thecreation target resource is not known to the receiver yet, the receivermay determine whether to create a resource by authenticating theoriginator. If the originator is authenticated, creation of a targetresource may be allowed. And, if identification information of thecreation target resource is included in the resource creation requestmessage, the receiver verifies whether or not the identificationinformation of the creation target resource already exists in a resourcestructure of the receiver. If valid identification information is notprovided (e.g., if the identification information of the creation targetresource is overlapped), the receiver may assign identificationinformation of the creation target resource. Similarly, if the resourcecreation request message does not include the identification informationof the creation target resource, the receiver may assign identificationinformation of the creation target resource.

If the creation target resource is successfully created by the receiver,the receiver may transmit a response message including informationdescribed in the following to the sender.

-   -   to: originator ID    -   fr: receiver ID    -   cn: URI and/or content of the created resource

In another example, in order to retrieve information (e.g., attributeinformation) about a resource of the receiver, the originator may use ascheme shown in an example of FIG. 7. In this case, the originator maysend a retrieval request message (e.g., RETRIEVE request) to thereceiver to retrieve the information (e.g., attribute information) aboutthe resource of the receiver. The originator may retrieve all or a partof attributes from a target resource of the receiver using the retrievalrequest message. The retrieval request message may include informationdescribed in the following.

-   -   op: R (Retrieve)    -   to: URI of retrieval target resource    -   fr: originator ID

If the receiver receives the retrieval request message from theoriginator, the receiver verifies whether or not a retrieval targetresource exists with reference to URI of the retrieval target resourceincluded in the retrieval request message and checks whether or not theoriginator has permission for retrieving for the retrieval targetresource. If there is no retrieval target resource or the originatordoes not have proper permission for retrieving, the receiver may send anerror through a response message. On the other hand, if a retrievaltarget resource exists and the originator has proper permission forretrieving, the receiver may send a response message to the originator.The response message may include information described in the following.

-   -   to: originator ID    -   fr: receiver ID    -   cn: content of retrieval target resource

In still another example, the originator may use a procedure shown in anexample of FIG. 7 to update attribute information in a specific resourceof the receiver. In this case, the originator may send an update requestmessage (e.g., UPDATE request) to the receiver. The originator mayupdate the attribute information with a new value in the specificresource of the receiver using the update request message. The updaterequest message may include information described in the following.

-   -   op: U (Update)    -   to: URI of an update target resource    -   fr: originator ID    -   cn: information to be updated in the update target resource

If the receiver receives a update request message from the originator,the receiver verifies whether or not there exists an update targetresource in the update request message with reference to URI of theupdate target resource and checks whether the originator is authorizedto perform modifying the target resource. If there exists an updatetarget resource and the originator has been properly authorized, theupdate target resource may be updated by information to be updated(e.g., cn). If the update target resource is successfully updated, thereceiver may transmit a response message to the originator. The responsemessage may include information described in the following.

-   -   to: originator ID    -   fr: receiver ID    -   cn: operation result

In still another example, the originator may use a procedure shown in anexample of FIG. 7 to delete a specific resource of the receiver. In thiscase, the originator may send a deletion request message (e.g., DELETErequest) to the receiver. The deletion request message may includeinformation described in the following.

-   -   op: D (Delete)    -   to: URI of a deletion target resource    -   fr: sender ID

If the receiver receives the deletion request message from theoriginator, the receiver verifies whether or not there exists a deletiontarget resource with reference to URI of a deletion target resource inthe deletion request message and checks whether the originator isauthorized to delete the target resource. If there is no target resourceand the originator has not been authorized, the receiver may send anerror through a response message. On the other hand, if there exists atarget resource and the originator has been properly authorized, thereceiver may send a response message including information described inthe following to the originator.

-   -   to: originator ID    -   fr: receiver ID    -   cn: operation result

FIG. 8 illustrates an example of different entities interoperating witheach other in a M2M system.

Referring to FIG. 8, it shows an example that an AE (application 2)registered to an IN (infrastructure node) interoperates with a M2Mdevice. For example, the M2M device may include a sensor which is aphysical device, and the AE registered to the IN may retrieve a value ofthe sensor of the M2M device.

An AE (application1) existing on a M2M device reads a value from asensor and stores the value in a CSE (dcse) to which the AE isregistered in a resource form (e.g., <container> resource). To this end,the AE (application1) existing on the M2M device should register to theCSE existing in the M2M device. As shown in an example of FIG. 8, if theregistration of the AE is completed, information related to theregistered M2M application is stored in a form of a resourcedcse/applications/application1. For example, if a sensor value of theM2M device is stored by the AE (application1) in a container resourceunder the resource dcse/applications/application1, the AE (application2)registered to the IN (infrastructure node) may access the sensor value.And, in order for the AE (application2) to access the M2M device, the AE(application2) should be register to a CSE (ncse) of the IN(infrastructure node). Similar to the AE (application 1) register beingregistered to the CSE (dcse), information about the AE (application2) isstored in a resource ncse/applications/application2. And, the AE(application1) and the AE (application2) may communicate with each othervia the CSE (ncse) and the CSE (dcse) instead of directly communicatingwith each other. To this end, it is necessary for the CSE (ncse) and theCSE (dcse) to be register to each other. If the CSE (dcse) registers tothe CSE (ncse), information (e.g., link) related to dcse is stored undera resource ncse/cses/dcse resource. As such, the AE (application2) mayobtain a path capable of accessing information of the AE (application1)and may be then able to read a sensor value using the path.

FIG. 9 illustrates an example of a procedure related to a subscriptionresource.

In a M2M system (e.g., oneM2M), as a resource changes, an entityinterested in the change of the resource may subscribe to a notificationof the change. In this case, in order to subscribe to the notification,a resource for subscription should be configured. The resource forsubscription may be referred to as a subscription resource or a<subscription> resource. When a subscription resource iscreated/configured, if a modification/change satisfying a conditionconfigured in the subscription resource occurs in a subscription targetresource (also referred to as a subscribed-to resource or a subscribedresource), a device (or an entity) in which the subscription resource isconfigured may transmit a notification to an address configured in thesubscription resource. A device (or an entity) in which a subscriptionresource is configured and/or which includes a subscription targetresource is referred to as a hosting device (or a hosting entity). Forexample, a subscription target resource may exist in a CSE of a M2Mgateway. In this case, the M2M gateway is referred to as a hostingdevice and the CSE of the M2M gateway is referred to as a hosting CSE.

A subscription procedure may be performed using a subscription resourcein a resource-oriented manner. For example, a subscription resource maybe created to subscribe to a specific subscription target resource, acondition for subscription may be changed by modifying a subscriptionresource, and a subscription resource may be deleted when subscriptionis not needed anymore.

A subscription resource includes information about a subscription targetresource (or subscribed-to resource). A relation between thesubscription target resource and the subscription resource may berepresented as a parent-child relation. For example, a <container>resource including a subscription target resource may have a<subscription> resource as a child resource. When a parent subscriptiontarget resource is deleted, the <subscription> resource may be deleted.

If a subscription resource corresponds to a child resource, anotification for indicating a status change of a parent resource may bedelivered to an entity specified in a notificationURI attribute in thesubscription resource according to configuration (or attributeconfiguration) of the subscription resource. If an originator has aRETRIEVE (or READ) permission for a subscribable resource, theoriginator may create a subscription resource. The originator of thesubscription resource becomes a resource subscriber. If a modificationto a subscription target resource occurs, it is able to determinewhether to transmit a notification to the resource subscriber bycomparing the modification and a filtering attribute (e.g.,filterCriteria attribute) with each other.

In another example, a subscription resource may be created in a specificresource under a parent resource. In this case, the specific resourcemay correspond to a resource including a collection of subscriptionresources. The resource may be referred to as a subscription collectionresource. For example, a specific entity may create a subscriptionresource <subscription> as a structure of<resourceURI>/subscriptions/<subscription>. In this case, the specificentity may subscribe to a resource identified by resourceURI via thesubscription resource. If change occurs in the resource identified bythe resourceURI, a notification may be transmitted to the specificentity according to whether the filterCriteria attribute is satisfied.Further, in this example, a resource <resourceURI>/subscriptionscorresponds to a subscription collection resource.

A subscription resource (e.g., <subscription> resource) may have variousattributes and child resources. For example, the subscription resource(e.g., <subscription> resource) may have a notificationSchedule resourceas a child resource, which includes scheduling information fordelivering a notification. And, for example, the subscription resource(e.g., <subscription> resource) may have attributes shown in Table 1. InTable 1, R/W indicates read/write permission, and may correspond to oneof READ/WRITE (RW), READ ONLY (RO), or WRITE ONLY (WO). And, in Table 1,a multiplicity indicates the number of occurrence of a correspondingattribute in the <subscription> resource. Table 1 is just an example. Anattribute of a subscription resource may be configured in a manner ofbeing different from Table 1.

TABLE 1 Attribute Name of RW/RO/ <subscription> Multiplicity WODescription resourceType (rT) 1 WO Resource Type. This WO resourceTypeattribute stores <in a two capital letters token> the information usefulfor procedure processing, e.g. CO for <container>, CI for <instance>.expirationTime (eT) 1 RW Time/date after which the resource will bedeleted by the hosting CSE. This attribute can be provided by theissuer, and in such a case it will be regarded as a hint to the hostingCSE on the lifetime of the resource. The hosting CSE can however decideon the real expirationTime. If the hosting CSE decides to change theexpirationTime attribute value, this is communicated back to theOriginator. The lifetime of the resource can: be extended by providing anew value for this attribute in an UPDATE verb. Or by deleting theattribute value, e.g. by not providing the attribute when doing a fullUPDATE, in which case the hosting CSE can decide on a new value.parentID (pID) 1 RO The flat URI used to identify the parent resourcewithout using the full structured URI. creationTime (cT) 1 RO Time/dateof creation of the resource. lastModifiedTime (IMT) 1 RO Lastmodification time/date of the resource. filterCriterion (fC) 0 . . . 1RW Criteria to be used to filter the results. They can either be used ina GET (as query parameters) or in a subscription. labels (IBs) 1 RWTokens, used as keys for discovering resources. accessRightID (aRI) 0 .. . 1 RW The URI of an <aceess rights> resource. The permissions definedin the <accessRight> resource that are referenced determine who isallowed to access the resource containing this attribute for a specificpurpose (e.g., Retrieve, Update, Delete etc.). If no accessRightID isgiven at the time of creation, the accessRightID of the parent resourceis linked to this attribute. expirationCounter 0 . . . 1 RW When thenumber of notifications becomes the same as this counter, the<subscription> resource shall be deleted. notificationURI 1 . . . n RWURI where the resource subscriber will receive notifications.aggregationURI 0 . . . 1 RW URI to aggregate notifications from groupmembers of a <group> resource. batchNotify 0 . . . 1 RW Indicates thatnotifications should be batched for delivery. When set, notificationevents are temporarily stored until either a specified number is readyto send or until a duration after the first noticifaction event hasexpired. rateLimit 0 . . . 1 RW Indicates that notifications should berate-limited. When set, notification events that exceed a specifiednumber within a specified time are temporarily stored then sent when thenumber of events sent per specified time falls below the limit.priorSubscriptionNotify 0 . . . 1 WO Indicates that when thissubscription is created, whether notification events prior tosubscription should be sent, e.g. send prior “n” notifications, ifavailable. interimEventsNotify 0 . . . 1 RW Indicates the notificationaction to be taken following a period of unreachability, when theresource subscriber becomes reachable (e.g. send “n” iterimnotifications, if available.) notificationStoragePriority 0 . . . 1 RWIndicates a priority for this subscription relative to othersubscriptions belonging to this same subscriber for retention ofnotification events when storage is congested. The storage congestionpolicy which uses this attribute as input is specified in section TBD.notificationStructure 1 RW Type of information that shall be containedin notifications. E.g., modified attribute only of a subscribed-toresource, a whole subscribed-to resource, and/or URI of a corresponding<subscription> resource.

In an example of Table 1, a filtering attribute (e.g., filterCriteria)corresponds to a list of conditions for modification/change of asubscription target resource, and each of the conditions may be in alogical AND relation. For example, when the filtering attribute (e.g.,filterCriteria) includes two conditions, if modification/change of asubscription target resource satisfies all of the two conditions, anotification may be transmitted. An amount of a notification message maybe adjusted by configuring a filtering attribute to a subscriptionresource. If a notification is configured to be transmitted to anotification target entity only when the configured filtering attributeis satisfied, the problem of excessive notification messages may beprevented. Table 2 shows an example of conditions that may be includedin the filtering attribute.

TABLE 2 Condition tag Matching condition createdBefore The creationTimeattribute of the subscribed resource is chronologically before thespecified value. createdAfter The creationTime attribute of thesubscribed resource is chronologically after the specified, value.modifiedSince The lastModifiedTime attribute of the subscribed resourceis chronologically after the specified value. unmodifiedSince ThelastModifiedTime attribute of the subscribed resource is chronologicallybefore the specified value. expireBefore The expirationTime attribute ofthe subscribed resource is chronologically before the specified value.expireAfter The expirationTime attribute of the subscribed resource ischronologically after the specified value. labels The labels attributesof the subscribed resource matches the specified value. respurceType TheresourceType attribute of the subscribed resource is the same as thespecified value. sizeAbove The contentSize attribute of the <instance>resource is equal to or greater than the specified value. sizeBelow ThecontentSize attribute of the <instance> resource is smaller than thespecified value. contentType The typeOfContent attribute of the<instance> resource matches the specified value limit Limitation thenumber of matching resources to the specified value.

Referring to FIG. 9, device 1 910 may perform a procedure shown in FIG.9 to subscribe to a specific resource of device 2 920. Device 1 910 mayor may not correspond to a target receiving a notification according tochange of a subscription target resource. In an example of FIG. 9, thespecific resource may correspond to the subscription target resource,and, since device 2 920 includes the subscription target resource,device 2 920 may correspond to a hosting device (or an entity).

In step S902, device 1 910 may transmit a request for a subscriptionresource to device 2 920 to subscribe to a specific resource. Forexample, the request for subscription resource may correspond to one ofa creation request of subscription resource, a retrieval request ofsubscription resource, a deletion request of subscription resource, oran update request of subscription resource. Each request may have a formof a request message according to the request-response scheme describedwith reference to FIG. 7. For example, if the request in step S902corresponds to a creation request, a request for a subscription resourcemay include op information including C (Create), cn informationincluding attribute information (e.g., notificationURI, filterCriteria,expirationTime, and the like) of the subscription resource, frinformation including identification information of device 1 910, and/orto information including identification information of device 2 920. Inanother example, if the request in step S920 corresponds to a retrievalrequest, a request for a subscription resource may include opinformation including R (Retrieve), fr information includingidentification information of device 1 910, to information includingidentification information of device 2 920, and/or cn informationindicating a retrieval target attribute. In still another example, ifthe request in step S902 corresponds to a deletion request or an updaterequest, a request for a subscription resource may include all or a partof information described with reference to FIG. 7.

In step S904, device 2 920 validates whether a request for asubscription resource is capable of being processed, and process therequest if the request is capable of being processed. For example, ifdevice 2 920 receives a creation request, device 2 920 validates whethera subscription target resource designated in the to information issubscribable, whether an originator (e.g., 910) of the request hasRETRIEVE permission for the subscription target resource, whether theoriginator (e.g., 910) of the request has access right for sending anotification to an entity or a device designated by the notificationURIif the notificationURI does not indicates the originator (e.g., 910) ofthe request, and whether a hosting device or an entity (e.g., 920) hasaccess rights for sending a notification to an entity or a devicedesignated by the notificationURI. If the aforementioned conditions areall satisfied, device 2 920 may create a subscription resource under asubscription target resource designated by to information.

In another example, if device 2 920 receives a retrieval request, device2 920 validates whether the originator (e.g., 910) of the request hasRETRIEVE permission for a subscription resource. If the aforementionedcondition is satisfied, device 2 920 may return all of the subscriptionresource or a part designated by the retrieval request of thesubscription resource.

In still another example, if device 2 920 receives an update request,device 2 920 may verify whether there exists a subscription resource andmay then validate whether an attribute corresponds to an attribute towhich WRITE can be performed and whether the originator (e.g., 910) ofthe request has permission to modify an attribute. If the aforementionedconditions are satisfied, device 2 920 updates the provided attribute.

In still another example, if device 2 920 receives a deletion request,device 2 920 validates whether the originator (e.g., 910) of the requesthas DELETE permission. If the aforementioned condition is satisfied,device 2 920 deletes a subscription resource.

In step S906, device 2 920 may send a response message to device 1 910after a request for a subscription resource is processed. The responsemessage of step S906 may have a form identical/similar to the responsemessage described with reference to FIG. 7. And, in case of theretrieval request, the response message may include information to bereturned.

FIG. 10 illustrates an example of a notification procedure. In theprocedure for notification, an originator may correspond to a device oran entity (e.g., 920) hosting a subscription resource. And, a receivermay correspond to a device (or an entity) indicated by addressinformation (e.g., notificationURI) configured in the subscriptionresource. Specific policy information may be configured for theprocedure for notification. The originator may be configured to send anotification message (e.g., NOTIFY) when the policy information issatisfied.

The notification message corresponds to a message triggered forinformation of a subscription resource. If change of a subscriptiontarget resource satisfies a filtering attribute configured in thesubscription resource, the notification message may be sent to areceiver indicated by the address information (e.g., notificationURI)configured in the subscription resource. The receiver of thenotification message may or may not correspond to a device or an entitywhich has created/configured the subscription resource. For example,device 1 910 may be identical to device 3 930 or may be different fromdevice 3 930. The notification message may include information describedin the following.

-   -   identification information or ID of originator (e.g., 920)    -   to: address information configured in subscription resource        (e.g., notificationURI)    -   cn: data representing modified content of subscription target        resource and/or subscription reference information (e.g., URI of        the subscription resource) which has created the notification        message

Referring to FIG. 10, in step S1002, originator 920 may detect/sense achange of a subscription target resource. The subscription targetresource corresponds to a parent resource of a subscription resource. Ifa resource or an attribute located at a same level as that of thesubscription resource under the subscription target resource ismodified/changed, originator 920 (e.g., SUB CSF or CSE, refer to FIG. 3)may recognize it as a change of the subscription target resource.

If the change of the subscription target resource is detected, in stepS1004, originator 920 checks whether the change is matched with afiltering attribute (e.g., filterCriteria) configured in thesubscription resource. For example, the filtering attribute may includeat least one attribute among the attributes shown in the example ofTable 2. If the change of the subscription target resource does notsatisfy any condition included in the filtering attribute, originator920 may ignore the change.

If the change of the subscription target resource satisfies allconditions included in the filtering attribute, in step S1006,originator 920 may transmit a notification message to entity 930indicated by address information (e.g., notificationURI) configured inthe subscription resource. For example, the notification message in stepS1006 may include identification information of originator 920, datarepresenting modified content of the subscription target resource,and/or subscription reference information which has created thenotification message.

FIG. 11 illustrates an example of using a subscription resource.

As described above, a subscription resource may be created/configured asa child resource of a specific resource, and a hosting device or anentity (or a M2M device or an entity in which the subscription resourceis created/configured) tracks a status change of a parent resource. If astatus change occurs in the parent resource, the hosting device sends anotification message with reference to a notification address (e.g.,notificationURI) of the subscription resource. In this case, forexample, a subscription/notification (SUB) common service function (CSF)of the M2M device in which the subscription resource iscreated/configured may take charge of tracking/monitoring the statuschange of the subscription target resource (e.g., refer to FIG. 3). TheM2M device may send a notification to an address (e.g., notificationURI)configured in the subscription resource whenever a modification/changeoccurs in a subscription target resource (e.g., a parent resource of thesubscription resource).

Although the M2M device in which the subscription resource iscreated/configured receives a request message for a specific operation,if there is no change of the subscription target resource, the M2Mdevice does not send a notification message. For example, if a retrievalrequest message (e.g., RETRIEVE request) is received from an externaldevice, since the M2M replies attribute information of a target resourcevia a response message, a change of the target resource does not occur.Hence, in this case, a notification message is not sent to an address(e.g., notificationURI) configured in the subscription resource. Assuch, if a change does not occur in the subscription target resource, asubscriber (or a subscription device) may not know whether there hasbeen an access to the subscription target resource.

In addition, as described above, a subscription resource (e.g.,<subscription> resource) may be created/configured to have aparent-child relation with a subscription target resource. When asubscription resource is created/configured, if another resource (e.g.,a child resource or an attribute of the subscription target resource)positioned at a same level as that of the subscription resource isdeleted, since a change has occurred in the subscription targetresource, a device (or SUB CSF of the device) sends a notificationmessage to an address (e.g., notificationURI) configured in thesubscription resource. However, in case that a resource is positioned ata level different from the level of the subscription resource, since theresource is not a target of the subscription resource, a change of theresource may not be identified using the subscription resource. Forexample, resources in a specific device may be configured to havedifferent access rights per level. For example, a parent resource and achild resource of the parent resource may have access rights differentfrom each other. In this case, when a subscription resource isconfigured, the subscription resource may operate for a correspondinglevel only and the subscription resource may not be applied to adifferent level.

Referring to FIG. 11, a subscription resource (e.g., <subscription>resource) may be created as a child resource of a specific resource(e.g., Resource1). In this case, the subscription resource correspondsto Resource 1 and a range capable of recognizing a change via thesubscription resource (e.g., <subscription> resource) corresponds to1130. However, a change satisfying a specific filtering condition viathe subscription resource (e.g., <subscription> resource) may not beidentified for a change of a resource or attribute positioned at a leveldifferent from a level of the subscription resource. For example, in anexample of FIG. 11, a change such as deletion of an attribute4 under a<container> resource may not be identified.

Further, since a subscription resource is created/configured as a childresource of a subscription target resource, if the subscription targetresource is deleted, the subscription resource is deleted as well.Hence, if the subscription target resource is deleted, since thesubscription resource itself is deleted, a subscriber may not receive anotification on deletion of the subscription target resource.

Similarly, a same problem may also occur when a resource is created. Ifa resource is created at a same level as a level of a subscriptionresource under a subscription target resource, since a change of thesubscription target resource occurs, a notification may be sent to asubscriber. However, since the subscription resource may not have accessrights for a resource of a different level, if a resource is created ina level different from the level of the subscription resource, anotification may not be sent to a subscriber. In order to subscribe to achange of a resource at a different level, it is necessary to separatelycreate/configure a resource as a child resource of a parent resource ofthe corresponding level.

For example, in an example of FIG. 11, if attribute5 is created underthe subscription target resource (e.g., Resource 1), device 2 920 checkswhether filtering information (e.g., filterCriteria) configured in thesubscription resource is satisfied. If the criteria information issatisfied, a notification may be transmitted to an address (e.g.,notificationURI) configured in the subscription resource. However, inthe example of FIG. 11, a change corresponding to a resource creation ata same level as the level of the subscription resource satisfies aspecific filtering condition (e.g., when a resource with attribute4having a specific value is created) may not be recognized.

The aforementioned problem may be solved in a manner of subscribing toan operation performed for a subscription target resource. For example,in case of performing an operation of retrieving the subscription targetresource, as mentioned in the foregoing description, since a retrievaloperation does not generate a change of the subscription targetresource, a notification message is not generated. However, if it ispossible to configure to subscribe to the retrieval operation, anotification message can be generated for the operation irrespective ofthe change of the subscription target resource when the operation ofretrieving the subscription target resource is performed.

Likewise, in case that a resource is created or deleted under asubscription resource, if it is able to configure the subscriptionresource to subscribe to a creation operation or a deletion operation,when a filtering attribute configured in a created or deleted targetresource is satisfied, a notification message may be generated.

Likewise, in case that a whole of a subscription target resource isdeleted, if it is able to configure the subscription resource tosubscribe to a deletion operation, since a notification message isgenerated before the subscription target resource and the subscriptionresource are deleted, it is possible to know the deletion of thesubscription target resource.

Hence, the present invention proposes a method of subscribing to aspecific operation performed in a M2M device. In particular, the presentinvention proposes to add condition information about a subscriptiontarget operation to a subscription resource to subscribe to the specificoperation. In more particular, the present invention proposes to add thecondition information about the subscription target operation to afiltering attribute (e.g., filterCriteria) of the subscription resource.The subscription target operation may correspond to a command forsubscription.

For example, the condition information about the subscription targetoperation may include first condition information indicating that anotification is to be performed when an operation of accessing asubscription target resource is matched with a specific value. The firstcondition information may enable monitoring to be performed on whetheran operation of accessing the subscription target resource is attemptedirrespective of whether or not the operation of accessing thesubscription target resource is performed. For example, the firstcondition information may have a name such as operationMonitor. Forexample, when a malicious application or devices attempt to access thesubscription target resource, there is no resource change due to accessrights. However, If the first condition information is configured in asubscription resource (or a filtering attribute), it is able to monitorthe malicious attempt. The first condition information may be set to astring argument such as Create, Retrieve, Update, Delete, or Notify.Condition information according to the present invention may beconfigured in addition to conditions shown in an example of Table 2.

According to the present invention, when a subscription target resourceis changed by a specific operation, the condition information about thesubscription target operation may include second condition informationindicating that a notification is to be performed when a changed statusof the subscription target resource is matched with a specific status.Together with the first condition information, the second conditioninformation may be useful for checking a resource status when thesubscription target operation is performed. The second conditioninformation may be set to a value or string indicating a status of aresource such as Created (or a child resource is created), Updated,Deleted (or a child resource is deleted). In addition, if a subscriptiontarget is deleted, the second condition may be set to Itself Deleted.For example, the second condition information may have a name such asresourceStatus.

Additionally, the condition information about the subscription targetoperation according to the present invention may include third conditioninformation indicating that a notification is to be performed when aresult of performing the subscription target operation corresponds to aspecific value and/or fourth condition information indicating that anotification is to be performed when identification information (e.g.,URI, ID) of a device (or an entity) which has sent a request message fora subscription resource corresponds to a specific value or string. Forexample, the third condition information may be set to a success code(e.g., Success, Okay, Okay and Done, Okay and Scheduled, Okay and InProgress), a failure code (e.g., Not okay) or an error code. Forexample, the fourth condition information may be set to identificationinformation of a device or entity having proper authority.

A hosting device/entity may prevent the first and the second conditioninformation from being configured as a filtering attribute at the sametime. Or, in case that the first and the second condition informationare configured as a filtering attribute at the same time, when the firstand the second condition information are configured for an identicaloperation, the second condition information may be preferentiallyconfigured (while the first condition information is ignored) and anotification for a corresponding operation is sent when the secondcondition information is satisfied. If either the first conditioninformation or the second condition information is configured for aspecific operation, a notification for the specific operation is sentwhen specific condition information (the first condition information orthe second condition information) is satisfied.

The condition information about the subscription target operation may bedelivered through a subscription resource creation procedure to a device(or CSE of the device) (or, a hosting device/entity) in which asubscription resource is created/configured. Or, the conditioninformation about the subscription target operation may be delivered tothe device/entity through an update procedure for the subscriptionresource. A request for a subscription resource may be transmitted inthe subscription resource creation procedure or the update procedure(refer to FIG. 9). Aside from the information described with referenceto FIG. 9, the request (e.g., in cn information) for the subscriptionresource may include information about a subscription target operation,information about a status of a resource to perform a notification aftera subscription target operation is performed, a result of performing asubscription target operation, and identification information (e.g.,URI, ID) of a device (or entity) which has sent a request message for asubscription resource. For example, the information about a status of aresource to perform a notification after a subscription target operationis performed may include Created, Deleted, Retrieved, Updated, and thelike. And, for example, the result of performing a subscription targetoperation may include a success code (e.g., Success, Okay, Okay andDone, Okay and Scheduled, Okay and In Progress), a failure code (e.g.,Not okay) or an error code.

Deliver when Subscription Resource is Created

Condition information about a subscription target operation according tothe present invention may be added to specific information in a creationrequest message (e.g., CREATE request) of a subscription resource. Forexample, the condition information about the subscription targetoperation may be included in en information of the creation requestmessage. Or, identification information of a device (or an entity),which has sent the subscription resource creation request message, maybe included in fr information of the creation request message.

Deliver by Updating Subscription Resource

Condition information about a subscription target operation according tothe present invention may be added to specific information in an updaterequest message (e.g., UPDATE request) of a subscription resource. Forexample, the condition information about the subscription targetoperation may be included in cn information of the update requestmessage. Or, identification information of a device (or an entity),which has sent the subscription resource update request message, may beincluded in fr information of the update request message.

If a receiver (e.g., a receiving device or an entity) receives conditioninformation about a subscription target operation via a request message,the receiver may add the condition information under a subscriptionresource. For example, the receiver may add the condition informationabout the subscription target operation to a filtering attribute (e.g.,filterCriteria) of the subscription resource.

If a request for a specific operation is received, a hosting device orentity checks whether the specific operation is related to asubscription target resource with reference to address information(e.g., to information) included in the request message. If the addressinformation included in the request message corresponds to URI of thesubscription target resource, it is able to determine whether thespecific operation corresponds to the subscription target operation withreference to the filtering attribute (e.g., filterCriteria) of thesubscription resource. If the specific operation corresponds to thesubscription target operation, the receiver may send a notification toan address (e.g., notificationURI) included in the subscriptionresource. In this case, for example, the notification message mayadditionally include a subscription target operation, a resource statusafter the subscription target operation is performed, or a result ofperforming the subscription target operation. For example, (attribute)information about the subscription target operation may include Create,Delete, Retrieve, Update, Notify, and the like. And, for example,(attribute) information about the resource status after the subscriptiontarget operation is performed may include Created (a child resource hasbeen created), Deleted (a child resource has been deleted), Updated,Itself Deleted (a corresponding resource has been deleted), and thelike. And, for example, the result of performing the subscription targetoperation may include a success code (e.g., Success, Okay, Okay andDone, Okay and Scheduled, Okay and In Progress), a failure code (e.g.,Not okay), or an error code. For example, if the address informationincluded in the request message is identical to URI of the subscriptiontarget resource or includes the URI of the subscription target resource,the address information included in the request message may correspondto the URI of the subscription target resource, and in this case it ispossible to subscribe to a specific operation according to configurationof the subscription resource.

FIG. 12 illustrates an exemplary method for an operation subscriptionaccording to the present invention. In FIG. 12, each device 910, 920,930 may include AE and/or CSE, and each step in FIG. 12 may be performedby the AE or the CSE included in each device 910, 920, 930.

Referring to FIG. 12, in step S1202, device 1 910 may send a requestmessage (e.g., CREATE request) to device 2 920 to create a subscriptionresource. In this case, the request message may include (attribute)information about a subscription target operation. If a subscriptionresource is already created, a request message (e.g., UPDATE request) toupdate a filtering attribute of the subscription resource may be sent,and the request message may include (attribute) information about asubscription target operation.

In step S1202, if the request message (e.g., CREATE request) forcreating the subscription resource is received, device 2 920 may createthe subscription resource using information included in the requestmessage. For example, device 2 920 creates the subscription resourcewith reference to a parent URI of the subscription resource included into information of the request message (e.g., CREATE request) and mayconfigure attributes of the subscription resource with reference toattribute information included in cn information. In this case, the(attribute) information about the subscription target operation may beset to a filtering attribute (e.g., filterCriteria) under thesubscription resource.

In step S1202, if the request message (e.g., UPDATE request) forupdating the subscription resource is received, device 2 920 may updatethe subscription resource using information included in the requestmessage. For example, device 2 920 may identify a position of thesubscription resource with reference to URI of the subscription resourceincluded in to information of the request message (e.g., UPDATE request)and may update filtering attribute (e.g., filterCriteria) of thesubscription resource using (attribute) information about thesubscription target operation included in cn information. Or, if URI ofthe filtering attribute of the subscription resource is included in toinformation of the request message (e.g., UPDATE request) and all or apart of the filtering attribute is included in cn information, device 2920 may update the filtering attribute (e.g., filterCriteria) of thesubscription resource.

Having received the (attribute) information about the subscriptiontarget operation via step S1202 and step S1204, device 2 920 may add the(attribute) information about the subscription target operation to thefiltering attribute of the subscription resource. For example, if the(attribute) information about the subscription target operation includesinformation indicating the subscription target operation, device 2 920may add first condition information (e.g., operationMonitor) to thefiltering attribute of the subscription resource. Or, for example, ifthe (attribute) information about the subscription target operationincludes information indicating a status of a resource to perform anotification after the operation is performed, device 2 920 may addsecond condition information (e.g., resourceStatus) to the filteringattribute of the subscription resource. Or, for example, if the(attribute) information about the subscription target operation includesinformation indicating a result of performing the subscription targetoperation to perform a notification, device 2 920 may add thirdcondition information to the filtering attribute of the subscriptionresource. Or, for example, if the (attribute) information about thesubscription target operation includes identification information of aspecific device as a condition for performing a notification, device 2920 may add fourth condition information to the filtering attribute ofthe subscription resource.

Subsequently, in step S1206, device 2 920 may receive a request messagefor performing a specific operation (e.g., Create, Retrieve, Update,Delete and the like). The request message received in step S1206 mayinclude second information indicating first information corresponding toURI of a subscription target resource and/or second informationindicating an operation to be performed for the subscription targetresource (or a child resource of the subscription target resource).

In step S1208, device 2 920 determines whether a condition for sending anotification message is satisfied. For example, device 2 920 maydetermine whether or not a subscription target resource includes asubscription resource with reference to the first information. In thiscase, device 2 920 may determine whether or not the subscription targetresource corresponding to the first information is in a parent-childresource relation with the subscription resource. Or, for example,device 2 920 may determine whether or not the filtering attribute of thesubscription resource includes the condition information (e.g., first tofourth condition information) for operation subscription. Or, forexample, device 2 920 may determine whether or not the first conditioninformation of the filtering attribute of the subscription resourceincludes a variable corresponding to an operation indicated by thesecond information with reference to the second information. Or, forexample, when a status of the subscription target resource or a statusof a child resource of the subscription target resource is changed by anoperation, device 2 920 may determine whether or not the secondcondition information of the filtering attribute of the subscriptionresource includes a variable corresponding to a changed status. Or, forexample, device 2 920 may determine whether or not device 1 910 has aretrieval permission for the subscription target resource. Or, forexample, if device 1 910 and device 3 930 are different from each other,device 2 920 may determine whether or not device 1 910 has access rightsto send a notification message to device 3 930. If the aforementionedconditions are determined and all or a part of the conditions aresatisfied, device 2 920 may send a notification message to an entityindicated by address information (e.g., notificationURI) configured inthe subscription resource.

If all or a part of the conditions are satisfied in step S1208, in stepS1210, device 2 920 may send a notification message to an entityindicated by address information configured in the subscriptionresource. In the present example, if it is assumed that URI indicatingdevice 3 930 (or a specific entity or a resource in the device 3) hasbeen configured in the subscription resource, the notification messagemay be sent to device 3 930 (or a specific entity or a resource in thedevice 3). In the example of FIG. 12, device 1 910 and device 3 930 maybe the same or different from each other.

For example, if the first condition information is added to thefiltering attribute of the subscription resource, the notificationmessage sent in step S1210 may include information (e.g. informationcorresponding to the second information in step S1206) about thesubscription target operation. Similarly, if the second information isadded to the filtering attribute of the subscription resource, thenotification message may include information indicating a resourcestatus after the subscription target operation is performed. Similarly,if the third/fourth information is added to the filtering attribute ofthe subscription resource, the notification message may include thecorresponding information.

Although there is no change in a resource status since the subscriptiontarget operation corresponds to a retrieval operation, a notificationmessage may be sent through the method described in the example of FIG.12. And, if the subscription target operation corresponds to a creation(Create) operation, although a resource positioned at a level differentfrom a level of the subscription resource is created under thesubscription target resource, a notification message may be sent.Similarly, if the subscription target operation corresponds to adeletion (Delete) operation, although the entire subscription targetresource is deleted, a notification message may be sent.

Although a subscription resource is configured to subscribe to aspecific operation, if a status of the subscription target resourcechanges, as mentioned in the foregoing description, a notification maybe sent to an address configured in the subscription resource. Hence,although the specific operation does not satisfy a filtering attribute,the notification may be sent according to configuration of thesubscription resource. In this case, the notification message does notadditionally include information about a subscription target operation.For example, if the specific operation does not satisfy the filteringattribute and there is a status change of the subscription targetresource only, the notification message may include modified content,changed URI, additional information, or the like of the subscriptiontarget resource.

FIG. 13 illustrates an embodiment according to the present invention. Inthe example shown in FIG. 13, assume that subscription resource 1350 iscreated under CSEBase resource 1320. Hence, a subscription targetresource corresponds to CSEBase resource 1320. And, assume that firstcondition information and second condition information according to thepresent invention are set to filtering attribute 1352. For example, infiltering attribute 1352, assume that the second condition informationis configured as CREATED. And, assume that address information 1354 ofthe subscription resource is configured as URI of a smart gridmanagement server.

In the example of FIG. 13, assume that M2M device 910 operates as asmart meter and corresponds to an ADN (application dedicated node)without a common service layer. Hence, M2M device 910 has a constrainedcapability and may not store or manage data by itself. M2M device 910may store all metering data in M2M gateway 920. M2M device 910periodically may read an amount of power usage and may create anattribute under application resource 1332 of the M2M gateway 920 tostore an amount of power usage used for a corresponding period. Forexample, in order to store a measured amount of power usage for a year,the M2M device may create smartMeterVal attribute 1340. To this end, M2Mdevice 910 may send a creation request message to M2M gateway 920. Inthe present example, the creation request message may includeinformation described in the following.

-   -   op: Since this information indicates a requested operation, this        information is set to C (Create)    -   to: Since this information indicates a parent ID of a creation        target resource, this information is set to        “CSEBase/smartMeterAE”    -   fr: Since this information indicates originator identification        information of a creation request message, this information is        set to “smartMeterAE”    -   cn: This information includes “smartMeterVal” as a name of a        creation target attribute and data “100”

Having received the creation request message, M2M gateway 920 may createsmartMeterVal attribute 1340 using information included in the creationrequest message according to the aforementioned procedure. And, M2Mgateway 920 is able to know an operation related to a subscriptiontarget resource with reference to the to information and is able to knowthat the second condition information is configured as CREATED infiltering attribute 1352 with reference to filtering attribute 1352. Inthe present example, since the information (e.g., op) on the operationincluded in the creation request message is set to C (Create) andsmartMeterVal attribute 1340 is successfully created according to thecreation request message, M2M gateway 920 may determine it as theoperation satisfies the filtering attribute. Hence, M2M gateway 920 maysend a notification message to the smart grid management serverindicated by address information 1354 configured in the subscriptionresource. In this case, the notification message may include information(e.g., CREATE) about a subscription target operation and information(e.g., CREATED) about a resource status after the operation isperformed.

If M2M device 910 is unable to have resource creation right or has noright for smartMeterAE resource 1332, since M2M gateway 920 is unable tocreate the corresponding resource, a notification is not generated. Inthis case, although M2M device 910 has no proper right, if the firstcondition information according to the present invention is configuredin filtering attribute 1352 of the subscription resource only, anotification may be generated.

Meanwhile, if both the first condition information and the secondcondition information according to the present invention are notconfigured in filtering attribute 1352 of the subscription resource,although smartMeterVal attribute 1340 is successfully created, since achange of a resource does not correspond to a range of subscriptionresource 1350, a notification is not generated (due to an access rightproblem and the like). In this case, there may exist a problem in thatthe smart grid management server is unable to instantly know meteringinformation created by smart meter 910.

Using a combination of the first condition information and the thirdcondition information, if an operation specified by the first conditioninformation for a subscription target resource satisfies a condition fora success or a failure specified by third condition information, anotification may be performed. Of course, using a combination of thefourth condition information, if an originator condition specified byfourth condition information is satisfied, a notification may beperformed.

And, the first condition information and/or the second conditioninformation of the present invention may be used in combined withattributes shown in the example of Table 2. For example, if the firstcondition information is configured together with condition information(e.g., resourceType) related to a resource type, it is possible tomonitor an operation for a specific resource type. For example, if thefirst condition information is configured as CREATE and the conditioninformation (e.g., resourceType) related to the resource type isconfigured by <application> or <AE>, when an instance of an applicationentity resource type (<application> or <AE>) is created, a notificationmessage may be transmitted. In another example, if the first conditioninformation is configured together with condition information (e.g.,labels) related to a label of a specific resource, it may be able tomonitor an operation for a resource including the corresponding label.In still another example, if the first condition information isconfigured together with condition information (e.g., contentType)related to a specific content type, it is possible to monitor anoperation for a resource including the corresponding content type.

And, the second condition information (e.g., resourceStatus) of thepresent invention may also be used in combined with the attributes shownin the example of Table 2. For example, if the second conditioninformation is configured together with condition information (e.g.,resourceType) related to a resource type, it is possible to monitorwhether a result of an operation related to a specific resource typesatisfies the second condition information. In another example, if thefirst condition information is configured together with conditioninformation (e.g., labels) related to a label of a specific resource, itmay be able to monitor whether a result of an operation for a resourceincluding the corresponding label satisfies the second conditioninformation. In still another example, if the first conditioninformation is configured together with condition information (e.g.,contentType) related to a specific content type, it is possible tomonitor whether a result of an operation for a resource including thecorresponding content type satisfies the second condition information.

In the present specification, although it is not explicitly described inthe present invention, it may be clearly understood that a filteringattribute (e.g., filterCriteria) is configured to monitor variousoperations in a manner of combining the condition information shown inthe example of Table 2 with the condition information (e.g., firstcondition information to fourth condition information) according to thepresent invention.

If an operation subscription method according to the present inventionis applied, it is also able to subscribe to an operation by which aresource change does not occur. Hence, it is able to flexibly cope witha malicious attack such as DDOS attack. And, if the present invention isapplied, since it is also able to subscribe to a not executed command,it is able to efficiently handle an access right configuration error ofa specific device or a malicious attempt. Further, if the presentinvention is applied, since it is able to track a specific operation viaoperation subscription, it is able to construct statistic informationabout an operation performed for a specific resource. Still further, ifthe present invention is applied, since it is able to configure not onlya condition for a resource change but also a condition for a specificoperation, it is able to reduce an unnecessary notification message andselectively subscribe to an interested notification message only. Stillfurther, if the present invention is applied, it is able to updateinformation about a resource/attribute in real time via operationsubscription. As mentioned in the foregoing description, since theoperation subscription method according to the present inventionprovides significant technical effects and advantages.

An access control method capable of being applied to the operationsubscription method according to the present invention is described inthe following.

1. Operation subscription is allowed when having an access right for aretrieval operation.

2. Access right value for operation subscription of a specific operationmay be different from access right value for the specific operation. Forexample, different access right values may be used for retrieving aresource and subscribing a retrieval operation.

3. In case of having an access right for a specific operation,subscription to the specific operation is allowed. For example, in caseof having an access right for creating a resource, it is allowed tosubscribe a creation operation.

In case of sending a notification, if having a retrieve right for aresource sending the notification, a transmission of the notificationmay be allowed. On the other hand, if not having the retrieve right, thetransmission of the notification may not allowed.

FIG. 14 illustrates a block diagram of a device according toembodiment(s) of the present invention. In the present invention, eachof M2M gateway, M2M server, or M2M device may operate as a transmittingdevice 10 or a receiving device 20.

The transmitting device 10 and the receiving device 20 respectivelyinclude radio frequency (RF) units 13, 23 for transmitting and receivingradio signals carrying information, data, signals, and/or messages,memories 12, 22 for storing information related to communication in awireless communication system, and processors 11, 21 operativelyconnected to the RF units 13, 23 and the memories 12, 22 and configuredto control the memories 12, 22 and/or the RF units 13, 23 so as toperform at least one of the above-described embodiments of the presentinvention.

The memories 12, 22 may store programs for processing and control of theprocessors 11, 21 and may temporarily storing input/output information.The memories 12, 22 may be used as buffers.

The processors 11, 21 control the overall operation of various modulesin the transmitting device 10 or the receiving device 20. The processors11, 21 may perform various control functions to implement the presentinvention. The processors 11, 21 may be controllers, microcontrollers,microprocessors, or microcomputers. The processors 11, 21 may beimplemented by hardware, firmware, software, or a combination thereof.In a hardware configuration, Application Specific Integrated Circuits(ASICs), Digital Signal Processors (DSPs), Digital Signal ProcessingDevices (DSPDs), Programmable Logic Devices (PLDs), or FieldProgrammable Gate Arrays (FPGAs) may be included in the processors 11,21. If the present invention is implemented using firmware or software,firmware or software may be configured to include modules, procedures,functions, etc. performing the functions or operations of the presentinvention. Firmware or software configured to perform the presentinvention may be included in the processors 11, 21 or stored in thememories 12, 22 so as to be driven by the processors 11, 21.

The processor 11 of the transmitting device 10 is scheduled from theprocessor 11 or a scheduler connected to the processor 11 and codes andmodulates signals and/or data to be transmitted to the outside. Thecoded and modulated signals and/or data are transmitted to the RF unit13. A signal processing process of the receiving device 20 is thereverse of the signal processing process of the transmitting device 10.Under the control of the processor 21, the RF unit 23 of the receivingdevice 10 receives RF signals transmitted by the transmitting device 10.The processor 21 decodes and demodulates the radio signals receivedthrough the receive antennas and restores data that the transmittingdevice 10 wishes to transmit.

The RF units 13, 23 include one or more antennas. An antenna performs afunction of transmitting signals processed by the RF units 13, 23 to theexterior or receiving radio signals from the exterior to transfer theradio signals to the RF units 13, 23. FIG. 14 illustrates that thetransmitting device and the receiving device communicate through RFunits respectively, but the present invention is not limited thereto. Inthe present invention, the transmitting device and the receiving devicemay communicate through a wired network. In this case, the RF unit maybe replaced with a network interface unit (NIU).

The embodiments of the present invention described above arecombinations of elements and features of the present invention. Theelements or features may be considered selective unless otherwisementioned. Each element or feature may be practiced without beingcombined with other elements or features. Further, an embodiment of thepresent invention may be constructed by combining parts of the elementsand/or features. Operation orders described in embodiments of thepresent invention may be rearranged. Some constructions of any oneembodiment may be included in another embodiment and may be replacedwith corresponding constructions of another embodiment. It is obvious tothose skilled in the art that claims that are not explicitly cited ineach other in the appended claims may be presented in combination as anembodiment of the present invention or included as a new claim by asubsequent amendment after the application is filed.

Specific operations to be conducted by the base station in the presentinvention may also be conducted by an upper node of the base station asnecessary. In other words, it will be obvious to those skilled in theart that various operations for enabling the base station to communicatewith the terminal in a network composed of several network nodesincluding the base station will be conducted by the base station orother network nodes other than the base station. The base station may bereferred to as a fixed station, a node-B (NB), an evolved node-B (eNB),an access point (AP), etc. A terminal may be referred to as a userequipment (UE), a mobile station (MS), a mobile subscriber station(MSS), etc.

The embodiments of the present invention may be implemented by variousmeans, for example, hardware, firmware, software, or a combinationthereof. In a hardware implementation, an embodiment of the presentinvention may be implemented by one or more application specificintegrated circuits (ASICs), digital signal processors (DSPs), digitalsignal processing devices (DSDPs), programmable logic devices (PLDs),field programmable gate arrays (FPGAs), processors, controllers,microcontrollers, microprocessors, etc.

In a firmware or software implementation, an embodiment of the presentinvention may be implemented in the form of a module, a procedure, afunction, etc. Software code may be stored in a memory unit and executedby a processor. The memory unit is located at the interior or exteriorof the processor and may transmit and receive data to and from theprocessor via various known means.

It will be apparent to those skilled in the art that variousmodifications and variations can be made in the present inventionwithout departing from the spirit or scope of the invention. Thus, it isintended that the present invention cover the modifications andvariations of this invention provided they come within the scope of theappended claims and their equivalents.

INDUSTRIAL APPLICABILITY

The present invention is applicable to a communication apparatus such asa terminal, a server, a gateway, etc.

What is claimed is:
 1. A method performed by a Machine-to-Machine (M2M)device in which a first resource and a second resource are configured,the method comprising: adding first condition information or secondcondition information to a filtering attribute of the first resource;receiving a request message from a first entity, the request messagecomprising first information indicating an address corresponding to thesecond resource and second information indicating an operation to beperformed by the device; and when a specific condition is satisfied,sending a notification message to a second entity indicated by addressinformation configured in the first resource, wherein the specificcondition includes the following conditions (1) to (3): (1) the secondresource corresponds to a parent resource of the first resource, (2)when the filtering attribute of the first resource comprises the firstcondition information, the first condition information comprises avariable corresponding to the operation, (3) when the filteringattribute of the first resource comprises the second conditioninformation, and when the second resource or a child resource of thesecond resource is changed by the operation, the second conditioninformation comprises a variable corresponding to a changed status ofthe second resource or the child resource of the second resource, andwherein each of the first resource and the second resource represents adata structure which is uniquely addressable using a unique address. 2.The method of claim 1, wherein the first condition information is usedfor monitoring whether an operation of accessing the second resource orthe child resource of the second resource is attempted irrespective ofwhether the operation of accessing the second resource or the childresource of the second resource is performed.
 3. The method of claim 1,wherein the variable indicates at least one of creation, retrieval,update, or deletion.
 4. The method of claim 1, wherein the notificationmessage comprises a parameter corresponding to the operation.
 5. Themethod of claim 1, wherein when the second condition information isadded to the filtering attribute of the first resource, the notificationmessage comprises a parameter corresponding to the changed status. 6.The method of claim 1, wherein the specific condition further includesthe following conditions (4) to (5): (4) the second entity sending therequest message has a retrieve permission for the second resource, (5)when the first entity and the second entity are different from eachother, the first entity has an access right for sending a notificationmessage to the second entity.
 7. The method of claim 1, wherein thefirst resource corresponds to a resource for subscription, and thesecond resource corresponds to a subscription target resource.
 8. AMachine-to-Machine (M2M) device in which a first resource and a secondresource are configured, the M2M device comprising: a network interfaceunit; and a processor, the processor configured to: add first conditioninformation or second condition information to a filtering attribute ofthe first resource, receive a request message from a first entity, therequest message comprising first information indicating an addresscorresponding to the second resource and second information indicatingan operation to be performed by the device, when a specific condition issatisfied, send a notification message to a second entity indicated byaddress information configured in the first resource, wherein thespecific condition includes the following conditions (1) to (3): (1) thesecond resource corresponds to a parent resource of the first resource,(2) when the filtering attribute of the first resource comprises thefirst condition information, the first condition information comprises avariable corresponding to the operation, (3) when the filteringattribute of the first resource comprises the second conditioninformation, and when the second resource or a child resource of thesecond resource is changed by the operation, the second conditioninformation comprises a variable corresponding to a changed status ofthe second resource or the child resource of the second resource, andwherein each of the first resource and the second resource represents adata structure which is uniquely addressable using a unique address. 9.The M2M device of claim 8, wherein the first condition information isused for monitoring whether an operation of accessing the secondresource or the child resource of the second resource is attemptedirrespective of whether the operation of accessing the second resourceor the child resource of the second resource is performed.
 10. The M2Mdevice of claim 8, wherein the variable indicates at least one ofcreation, retrieval, update, or deletion.
 11. The M2M device of claim 8,wherein the notification message comprises a parameter corresponding tothe operation.
 12. The M2M device of claim 8, wherein when the secondcondition information is added to the filtering attribute of the firstresource, the notification message comprises a parameter correspondingto the changed status.
 13. The M2M device of claim 8, wherein thespecific condition further includes the following conditions (4) to (5):(4) the second entity sending the request message has a retrievepermission for the second resource, (5) when the first entity and thesecond entity are different from each other, the first entity has anaccess right for sending a notification message to the second entity.14. The M2M device of claim 8, wherein the first resource corresponds toa resource for subscription, and the second resource corresponds to asubscription target resource.